As it is well known, in the present telecommunications environments, the demand is increasingly pointing toward the provision of greater bandwidth capacity. In the future waves of broadband deployment, service providers are likely to focus on offering a set, as complete as possible, of services in the various domains of voice, data and video to the very household of the end users. These services comprise, for example, video on demand (VoD), HDTV and broadcast TV services for all subscribers simultaneously. In order to achieve this goal broadband access capability is required on the same conventional network implemented for narrowband applications. This means that transmission is made at the broadband and the narrowband rates simultaneously each rate being used for a particular application, e.g. broadband for data communication and narrowband for voice communication.
The simultaneous transmission of broadband and narrowband brings about the need for combining the two types of signal into one in transmission and separating (splitting) the two types of signal into two independent signals at reception.
In the conventional practice, the task of combining and splitting the broadband and the narrowband signals is done by means of the so-called “splitters”. A splitter is therefore a device used in telephony in order to split a telephone signal into two or more signals of different frequencies, or combine signals of different frequencies to form a single combined signal. Splitters are typically installed at central offices and may be needed at customer premises.
One drawback associated with the use of splitters is the wiring work involved in providing a subscriber to a new service is complicated and time consuming. Whenever a new service is activated, for example for providing xDSL service to a user who is already connected to POTS services, the subscriber loop needs to be rewired. This in turn, requires that a technician visits the respective service delivery site, for example a central office or a cabinet, in order to perform the rewiring tasks. The consequence is an increase in costs for providing the new service mainly due to manpower expenses, and perhaps loss of revenue as the service would become available after certain delay, namely only after the completion of the rewiring work.
In order to overcome the above drawbacks solutions have been proposed in order to simplify the use of splitters. One such solution comprises the use of combination line termination cards (hereinafter referred to as “combination cards”). These cards are adapted for combining broadband and narrowband transmissions without using external splitters. These units are single cards that handle both the narrowband access and the broadband access. In order to separate the high rate and the low rate signals from each other, without using an external splitter, combination cards use low pass and high pass filters incorporated inside them.
However, the combination cards also present important drawbacks. These drawbacks can be described within three basic categories:                i—the rigidity of the solution in terms of future evolution;        ii—the upfront investment required for their installation; and        iii—the impact on narrowband service availability caused by a failure in the broadband service.        
These drawbacks are described in further details below:                i—As regards the rigidity of the solution, it is a well known fact in the related art that in a combination card, both the broadband electronics and the narrowband electronics are present in the same physical unit. While narrowband telephony is a very stable technology due to the fact that the existing networks and services need no—or very little—change for their continuing availability, and the operators tend to want to make their investment in such technology last as long as possible (dozens of years or even more); the broadband access technology is changing very rapidly. Furthermore, it is a well known fact that broadband access technology will very probably change significantly every 2-3 years. This strong tendency for change together with the overwhelming demand from the end users for new services, force the operators to replace the already installed plants relatively frequently in their effort to keep up with the fast-changing demand and be compliant with the requirements of the new systems to be installed.        
Therefore, when broadband transmission/reception circuitry is combined in the same physical unit with narrowband transmission/reception circuitry, replacing the broadband part implies also replacing the narrowband part. As a consequence the related narrowband hardware that was intended for lasting many years is discarded, thus giving rise to an unnecessary loss in investment and installation costs.    ii—As regards upfront investment, it is known that the intended advantage of combination card solutions is that the operating expenditures would be reduced when a service is activated to a given user. However, with the integrated combination card solutions the investment already includes both broadband and narrowband hardware technologies from the outset, regardless of whether there would be an eventual need of both services. Thus if the user in question does not demand the combined service, the presence of both types of hardware in the unit gives rise to unnecessary expenditure.    iii—As regards service availability, it is well known that the narrowband telephony is regarded as a high availability service. A level of availability of about 99.999% is a common rate in the related industry. Broadband, on the other hand, has less stringent requirements. If in an integrated combination card the broadband part suffers a failure, the whole card needs to be replaced, thus resulting in the unavailability of the narrowband telephony service as well. The contrary would also be a drawback, namely any failure in the narrowband system, although less probable, would eventually impact the broadband service upon replacement of the single unit combination card.
In view of the above drawbacks, it is therefore desired to provide a line termination arrangement with combined broadband and narrowband services which overcomes the aforementioned drawbacks.